Housings for automotive electrical components such as lamps, sensors, and electronic control units (ECUs) are provided with vent members that prevent entry of foreign matters into the housings while ensuring ventilation between the interior and exterior of the housings. For example, Patent Literature 1 describes a gas-permeable membrane bonded or welded to the opening portion of an automotive lamp housing.
Patent Literature 1 discloses bonding and welding as examples of the method for fixing the gas-permeable membrane to a resin component such as a lamp housing. Bonding is an easy way but has disadvantages such as a relatively low productivity and a time-dependent decrease in bond strength. On the other hand, welding has the disadvantage of poor material compatibility. In particular, when the gas-permeable membrane is made of a fluororesin and the resin component is made of a thermoplastic resin, it is not easy to weld the gas-permeable membrane to the resin component. Therefore, a welding rib is conventionally provided on the surface of the resin component. The weld strength between the resin component and the gas-permeable membrane can be increased by melting and solidifying the welding rib on the surface of the resin component while pressing the gas-permeable membrane against the welding rib (Patent Literature 2).